The overall goal of this investigation is to characterize the long-term metabolic effects of pancreas transplantation and hemipancreas donation in humans. This on-going project will longitudunally assess the effects of pancreas and islet transplantation and hemipancreatectomy on glucose tolerance, insulin secretion, and insulin action. In addition, the pattern of pulsatile insulin secretion will be examined in hemipancreatectomized donors. This information will be of benefit to current and future pancreas and islet transplant recipients and will provide insights into the role of neural and endocrine modulators in the regulation of pancreatic function and glucose homeostasis.